Exhibit 4.3 AMENDMENT NO 1 TO RIGHTS AGREEMENT This Amendment No. 1 (the "Amendment"), dated as of March 20, 2001 is made by and between AutoImmune Inc., a Delaware corporation (the "Company"), and Computershare Trust Company, Inc. (formerly, American...Rights Agreement • March 23rd, 2001 • Autoimmune Inc • Biological products, (no disgnostic substances)
